kernel/init/initramfs.c

   1 /*
   2  * Many of the syscalls used in this file expect some of the arguments
   3  * to be __user pointers not __kernel pointers.  To limit the sparse
   4  * noise, turn off sparse checking for this file.
   5  */
   6 #ifdef __CHECKER__
   7 #undef __CHECKER__
   8 #warning "Sparse checking disabled for this file"
   9 #endif
  10
  11 #include <linux/init.h>
  12 #include <linux/fs.h>
  13 #include <linux/slab.h>
  14 #include <linux/types.h>
  15 #include <linux/fcntl.h>
  16 #include <linux/delay.h>
  17 #include <linux/string.h>
  18 #include <linux/dirent.h>
  19 #include <linux/syscalls.h>
  20 #include <linux/utime.h>
  21
  22 static ssize_t __init xwrite(int fd, const char *p, size_t count)
  23 {
  24         ssize_t out = 0;
  25
  26         /* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
  27         while (count) {
  28                 ssize_t rv = sys_write(fd, p, count);
  29
  30                 if (rv < 0) {
  31                         if (rv == -EINTR || rv == -EAGAIN)
  32                                 continue;
  33                         return out ? out : rv;
  34                 } else if (rv == 0)
  35                         break;
  36
  37                 p += rv;
  38                 out += rv;
  39                 count -= rv;
  40         }
  41
  42         return out;
  43 }
  44
  45 static __initdata char *message;
  46 static void __init error(char *x)
  47 {
  48         if (!message)
  49                 message = x;
  50 }
  51
  52 /* link hash */
  53
  54 #define N_ALIGN(len) ((((len) + 1) & ~3) + 2)
  55
  56 static __initdata struct hash {
  57         int ino, minor, major;
  58         umode_t mode;
  59         struct hash *next;
  60         char name[N_ALIGN(PATH_MAX)];
  61 } *head[32];
  62
  63 static inline int hash(int major, int minor, int ino)
  64 {
  65         unsigned long tmp = ino + minor + (major << 3);
  66         tmp += tmp >> 5;
  67         return tmp & 31;
  68 }
  69
  70 static char __init *find_link(int major, int minor, int ino,
  71                               umode_t mode, char *name)
  72 {
  73         struct hash **p, *q;
  74         for (p = head + hash(major, minor, ino); *p; p = &(*p)->next) {
  75                 if ((*p)->ino != ino)
  76                         continue;
  77                 if ((*p)->minor != minor)
  78                         continue;
  79                 if ((*p)->major != major)
  80                         continue;
  81                 if (((*p)->mode ^ mode) & S_IFMT)
  82                         continue;
  83                 return (*p)->name;
  84         }
  85         q = kmalloc(sizeof(struct hash), GFP_KERNEL);
  86         if (!q)
  87                 panic("can't allocate link hash entry");
  88         q->major = major;
  89         q->minor = minor;
  90         q->ino = ino;
  91         q->mode = mode;
  92         strcpy(q->name, name);
  93         q->next = NULL;
  94         *p = q;
  95         return NULL;
  96 }
  97
  98 static void __init free_hash(void)
  99 {
 100         struct hash **p, *q;
 101         for (p = head; p < head + 32; p++) {
 102                 while (*p) {
 103                         q = *p;
 104                         *p = q->next;
 105                         kfree(q);
 106                 }
 107         }
 108 }
 109
 110 static long __init do_utime(char *filename, time_t mtime)
 111 {
 112         struct timespec t[2];
 113
 114         t[0].tv_sec = mtime;
 115         t[0].tv_nsec = 0;
 116         t[1].tv_sec = mtime;
 117         t[1].tv_nsec = 0;
 118
 119         return do_utimes(AT_FDCWD, filename, t, AT_SYMLINK_NOFOLLOW);
 120 }
 121
 122 static __initdata LIST_HEAD(dir_list);
 123 struct dir_entry {
 124         struct list_head list;
 125         char *name;
 126         time_t mtime;
 127 };
 128
 129 static void __init dir_add(const char *name, time_t mtime)
 130 {
 131         struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
 132         if (!de)
 133                 panic("can't allocate dir_entry buffer");
 134         INIT_LIST_HEAD(&de->list);
 135         de->name = kstrdup(name, GFP_KERNEL);
 136         de->mtime = mtime;
 137         list_add(&de->list, &dir_list);
 138 }
 139
 140 static void __init dir_utime(void)
 141 {
 142         struct dir_entry *de, *tmp;
 143         list_for_each_entry_safe(de, tmp, &dir_list, list) {
 144                 list_del(&de->list);
 145                 do_utime(de->name, de->mtime);
 146                 kfree(de->name);
 147                 kfree(de);
 148         }
 149 }
 150
 151 static __initdata time_t mtime;
 152
 153 /* cpio header parsing */
 154
 155 static __initdata unsigned long ino, major, minor, nlink;
 156 static __initdata umode_t mode;
 157 static __initdata unsigned long body_len, name_len;
 158 static __initdata uid_t uid;
 159 static __initdata gid_t gid;
 160 static __initdata unsigned rdev;
 161
 162 static void __init parse_header(char *s)
 163 {
 164         unsigned long parsed[12];
 165         char buf[9];
 166         int i;
 167
 168         buf[8] = '\0';
 169         for (i = 0, s += 6; i < 12; i++, s += 8) {
 170                 memcpy(buf, s, 8);
 171                 parsed[i] = simple_strtoul(buf, NULL, 16);
 172         }
 173         ino = parsed[0];
 174         mode = parsed[1];
 175         uid = parsed[2];
 176         gid = parsed[3];
 177         nlink = parsed[4];
 178         mtime = parsed[5];
 179         body_len = parsed[6];
 180         major = parsed[7];
 181         minor = parsed[8];
 182         rdev = new_encode_dev(MKDEV(parsed[9], parsed[10]));
 183         name_len = parsed[11];
 184 }
 185
 186 /* FSM */
 187
 188 static __initdata enum state {
 189         Start,
 190         Collect,
 191         GotHeader,
 192         SkipIt,
 193         GotName,
 194         CopyFile,
 195         GotSymlink,
 196         Reset
 197 } state, next_state;
 198
 199 static __initdata char *victim;
 200 static unsigned long byte_count __initdata;
 201 static __initdata loff_t this_header, next_header;
 202
 203 static inline void __init eat(unsigned n)
 204 {
 205         victim += n;
 206         this_header += n;
 207         byte_count -= n;
 208 }
 209
 210 static __initdata char *vcollected;
 211 static __initdata char *collected;
 212 static long remains __initdata;
 213 static __initdata char *collect;
 214
 215 static void __init read_into(char *buf, unsigned size, enum state next)
 216 {
 217         if (byte_count >= size) {
 218                 collected = victim;
 219                 eat(size);
 220                 state = next;
 221         } else {
 222                 collect = collected = buf;
 223                 remains = size;
 224                 next_state = next;
 225                 state = Collect;
 226         }
 227 }
 228
 229 static __initdata char *header_buf, *symlink_buf, *name_buf;
 230
 231 static int __init do_start(void)
 232 {
 233         read_into(header_buf, 110, GotHeader);
 234         return 0;
 235 }
 236
 237 static int __init do_collect(void)
 238 {
 239         unsigned long n = remains;
 240         if (byte_count < n)
 241                 n = byte_count;
 242         memcpy(collect, victim, n);
 243         eat(n);
 244         collect += n;
 245         if ((remains -= n) != 0)
 246                 return 1;
 247         state = next_state;
 248         return 0;
 249 }
 250
 251 static int __init do_header(void)
 252 {
 253         if (memcmp(collected, "070707", 6)==0) {
 254                 error("incorrect cpio method used: use -H newc option");
 255                 return 1;
 256         }
 257         if (memcmp(collected, "070701", 6)) {
 258                 error("no cpio magic");
 259                 return 1;
 260         }
 261         parse_header(collected);
 262         next_header = this_header + N_ALIGN(name_len) + body_len;
 263         next_header = (next_header + 3) & ~3;
 264         state = SkipIt;
 265         if (name_len <= 0 || name_len > PATH_MAX)
 266                 return 0;
 267         if (S_ISLNK(mode)) {
 268                 if (body_len > PATH_MAX)
 269                         return 0;
 270                 collect = collected = symlink_buf;
 271                 remains = N_ALIGN(name_len) + body_len;
 272                 next_state = GotSymlink;
 273                 state = Collect;
 274                 return 0;
 275         }
 276         if (S_ISREG(mode) || !body_len)
 277                 read_into(name_buf, N_ALIGN(name_len), GotName);
 278         return 0;
 279 }
 280
 281 static int __init do_skip(void)
 282 {
 283         if (this_header + byte_count < next_header) {
 284                 eat(byte_count);
 285                 return 1;
 286         } else {
 287                 eat(next_header - this_header);
 288                 state = next_state;
 289                 return 0;
 290         }
 291 }
 292
 293 static int __init do_reset(void)
 294 {
 295         while (byte_count && *victim == '\0')
 296                 eat(1);
 297         if (byte_count && (this_header & 3))
 298                 error("broken padding");
 299         return 1;
 300 }
 301
 302 static int __init maybe_link(void)
 303 {
 304         if (nlink >= 2) {
 305                 char *old = find_link(major, minor, ino, mode, collected);
 306                 if (old)
 307                         return (sys_link(old, collected) < 0) ? -1 : 1;
 308         }
 309         return 0;
 310 }
 311
 312 static void __init clean_path(char *path, umode_t fmode)
 313 {
 314         struct stat st;
 315
 316         if (!sys_newlstat(path, &st) && (st.st_mode ^ fmode) & S_IFMT) {
 317                 if (S_ISDIR(st.st_mode))
 318                         sys_rmdir(path);
 319                 else
 320                         sys_unlink(path);
 321         }
 322 }
 323
 324 static __initdata int wfd;
 325
 326 static int __init do_name(void)
 327 {
 328         state = SkipIt;
 329         next_state = Reset;
 330         if (strcmp(collected, "TRAILER!!!") == 0) {
 331                 free_hash();
 332                 return 0;
 333         }
 334         clean_path(collected, mode);
 335         if (S_ISREG(mode)) {
 336                 int ml = maybe_link();
 337                 if (ml >= 0) {
 338                         int openflags = O_WRONLY|O_CREAT;
 339                         if (ml != 1)
 340                                 openflags |= O_TRUNC;
 341                         wfd = sys_open(collected, openflags, mode);
 342
 343                         if (wfd >= 0) {
 344                                 sys_fchown(wfd, uid, gid);
 345                                 sys_fchmod(wfd, mode);
 346                                 if (body_len)
 347                                         sys_ftruncate(wfd, body_len);
 348                                 vcollected = kstrdup(collected, GFP_KERNEL);
 349                                 state = CopyFile;
 350                         }
 351                 }
 352         } else if (S_ISDIR(mode)) {
 353                 sys_mkdir(collected, mode);
 354                 sys_chown(collected, uid, gid);
 355                 sys_chmod(collected, mode);
 356                 dir_add(collected, mtime);
 357         } else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 358                    S_ISFIFO(mode) || S_ISSOCK(mode)) {
 359                 if (maybe_link() == 0) {
 360                         sys_mknod(collected, mode, rdev);
 361                         sys_chown(collected, uid, gid);
 362                         sys_chmod(collected, mode);
 363                         do_utime(collected, mtime);
 364                 }
 365         }
 366         return 0;
 367 }
 368
 369 static int __init do_copy(void)
 370 {
 371         if (byte_count >= body_len) {
 372                 if (xwrite(wfd, victim, body_len) != body_len)
 373                         error("write error");
 374                 sys_close(wfd);
 375                 do_utime(vcollected, mtime);
 376                 kfree(vcollected);
 377                 eat(body_len);
 378                 state = SkipIt;
 379                 return 0;
 380         } else {
 381                 if (xwrite(wfd, victim, byte_count) != byte_count)
 382                         error("write error");
 383                 body_len -= byte_count;
 384                 eat(byte_count);
 385                 return 1;
 386         }
 387 }
 388
 389 static int __init do_symlink(void)
 390 {
 391         collected[N_ALIGN(name_len) + body_len] = '\0';
 392         clean_path(collected, 0);
 393         sys_symlink(collected + N_ALIGN(name_len), collected);
 394         sys_lchown(collected, uid, gid);
 395         do_utime(collected, mtime);
 396         state = SkipIt;
 397         next_state = Reset;
 398         return 0;
 399 }
 400
 401 static __initdata int (*actions[])(void) = {
 402         [Start]         = do_start,
 403         [Collect]       = do_collect,
 404         [GotHeader]     = do_header,
 405         [SkipIt]        = do_skip,
 406         [GotName]       = do_name,
 407         [CopyFile]      = do_copy,
 408         [GotSymlink]    = do_symlink,
 409         [Reset]         = do_reset,
 410 };
 411
 412 static long __init write_buffer(char *buf, unsigned long len)
 413 {
 414         byte_count = len;
 415         victim = buf;
 416
 417         while (!actions[state]())
 418                 ;
 419         return len - byte_count;
 420 }
 421
 422 static long __init flush_buffer(void *bufv, unsigned long len)
 423 {
 424         char *buf = (char *) bufv;
 425         long written;
 426         long origLen = len;
 427         if (message)
 428                 return -1;
 429         while ((written = write_buffer(buf, len)) < len && !message) {
 430                 char c = buf[written];
 431                 if (c == '0') {
 432                         buf += written;
 433                         len -= written;
 434                         state = Start;
 435                 } else if (c == 0) {
 436                         buf += written;
 437                         len -= written;
 438                         state = Reset;
 439                 } else
 440                         error("junk in compressed archive");
 441         }
 442         return origLen;
 443 }
 444
 445 static unsigned long my_inptr; /* index of next byte to be processed in inbuf */
 446
 447 #include <linux/decompress/generic.h>
 448
 449 static char * __init unpack_to_rootfs(char *buf, unsigned long len)
 450 {
 451         long written;
 452         decompress_fn decompress;
 453         const char *compress_name;
 454         static __initdata char msg_buf[64];
 455
 456         header_buf = kmalloc(110, GFP_KERNEL);
 457         symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
 458         name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
 459
 460         if (!header_buf || !symlink_buf || !name_buf)
 461                 panic("can't allocate buffers");
 462
 463         state = Start;
 464         this_header = 0;
 465         message = NULL;
 466         while (!message && len) {
 467                 loff_t saved_offset = this_header;
 468                 if (*buf == '0' && !(this_header & 3)) {
 469                         state = Start;
 470                         written = write_buffer(buf, len);
 471                         buf += written;
 472                         len -= written;
 473                         continue;
 474                 }
 475                 if (!*buf) {
 476                         buf++;
 477                         len--;
 478                         this_header++;
 479                         continue;
 480                 }
 481                 this_header = 0;
 482                 decompress = decompress_method(buf, len, &compress_name);
 483                 pr_debug("Detected %s compressed data\n", compress_name);
 484                 if (decompress) {
 485                         int res = decompress(buf, len, NULL, flush_buffer, NULL,
 486                                    &my_inptr, error);
 487                         if (res)
 488                                 error("decompressor failed");
 489                 } else if (compress_name) {
 490                         if (!message) {
 491                                 snprintf(msg_buf, sizeof msg_buf,
 492                                          "compression method %s not configured",
 493                                          compress_name);
 494                                 message = msg_buf;
 495                         }
 496                 } else
 497                         error("junk in compressed archive");
 498                 if (state != Reset)
 499                         error("junk in compressed archive");
 500                 this_header = saved_offset + my_inptr;
 501                 buf += my_inptr;
 502                 len -= my_inptr;
 503         }
 504         dir_utime();
 505         kfree(name_buf);
 506         kfree(symlink_buf);
 507         kfree(header_buf);
 508         return message;
 509 }
 510
 511 static int __initdata do_retain_initrd;
 512
 513 static int __init retain_initrd_param(char *str)
 514 {
 515         if (*str)
 516                 return 0;
 517         do_retain_initrd = 1;
 518         return 1;
 519 }
 520 __setup("retain_initrd", retain_initrd_param);
 521
 522 extern char __initramfs_start[];
 523 extern unsigned long __initramfs_size;
 524 #include <linux/initrd.h>
 525 #include <linux/kexec.h>
 526
 527 static void __init free_initrd(void)
 528 {
 529 #ifdef CONFIG_KEXEC
 530         unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 531         unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
 532 #endif
 533         if (do_retain_initrd)
 534                 goto skip;
 535
 536 #ifdef CONFIG_KEXEC
 537         /*
 538          * If the initrd region is overlapped with crashkernel reserved region,
 539          * free only memory that is not part of crashkernel region.
 540          */
 541         if (initrd_start < crashk_end && initrd_end > crashk_start) {
 542                 /*
 543                  * Initialize initrd memory region since the kexec boot does
 544                  * not do.
 545                  */
 546                 memset((void *)initrd_start, 0, initrd_end - initrd_start);
 547                 if (initrd_start < crashk_start)
 548                         free_initrd_mem(initrd_start, crashk_start);
 549                 if (initrd_end > crashk_end)
 550                         free_initrd_mem(crashk_end, initrd_end);
 551         } else
 552 #endif
 553                 free_initrd_mem(initrd_start, initrd_end);
 554 skip:
 555         initrd_start = 0;
 556         initrd_end = 0;
 557 }
 558
 559 #ifdef CONFIG_BLK_DEV_RAM
 560 #define BUF_SIZE 1024
 561 static void __init clean_rootfs(void)
 562 {
 563         int fd;
 564         void *buf;
 565         struct linux_dirent64 *dirp;
 566         int num;
 567
 568         fd = sys_open("/", O_RDONLY, 0);
 569         WARN_ON(fd < 0);
 570         if (fd < 0)
 571                 return;
 572         buf = kzalloc(BUF_SIZE, GFP_KERNEL);
 573         WARN_ON(!buf);
 574         if (!buf) {
 575                 sys_close(fd);
 576                 return;
 577         }
 578
 579         dirp = buf;
 580         num = sys_getdents64(fd, dirp, BUF_SIZE);
 581         while (num > 0) {
 582                 while (num > 0) {
 583                         struct stat st;
 584                         int ret;
 585
 586                         ret = sys_newlstat(dirp->d_name, &st);
 587                         WARN_ON_ONCE(ret);
 588                         if (!ret) {
 589                                 if (S_ISDIR(st.st_mode))
 590                                         sys_rmdir(dirp->d_name);
 591                                 else
 592                                         sys_unlink(dirp->d_name);
 593                         }
 594
 595                         num -= dirp->d_reclen;
 596                         dirp = (void *)dirp + dirp->d_reclen;
 597                 }
 598                 dirp = buf;
 599                 memset(buf, 0, BUF_SIZE);
 600                 num = sys_getdents64(fd, dirp, BUF_SIZE);
 601         }
 602
 603         sys_close(fd);
 604         kfree(buf);
 605 }
 606 #endif
 607
 608 static int __init populate_rootfs(void)
 609 {
 610         char *err = unpack_to_rootfs(__initramfs_start, __initramfs_size);
 611         if (err)
 612                 panic("%s", err); /* Failed to decompress INTERNAL initramfs */
 613         if (initrd_start) {
 614 #ifdef CONFIG_BLK_DEV_RAM
 615                 int fd;
 616                 printk(KERN_INFO "Trying to unpack rootfs image as initramfs...\n");
 617                 err = unpack_to_rootfs((char *)initrd_start,
 618                         initrd_end - initrd_start);
 619                 if (!err) {
 620                         free_initrd();
 621                         goto done;
 622                 } else {
 623                         clean_rootfs();
 624                         unpack_to_rootfs(__initramfs_start, __initramfs_size);
 625                 }
 626                 printk(KERN_INFO "rootfs image is not initramfs (%s)"
 627                                 "; looks like an initrd\n", err);
 628                 fd = sys_open("/initrd.image",
 629                               O_WRONLY|O_CREAT, 0700);
 630                 if (fd >= 0) {
 631                         ssize_t written = xwrite(fd, (char *)initrd_start,
 632                                                 initrd_end - initrd_start);
 633
 634                         if (written != initrd_end - initrd_start)
 635                                 pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 636                                        written, initrd_end - initrd_start);
 637
 638                         sys_close(fd);
 639                         free_initrd();
 640                 }
 641         done:
 642 #else
 643                 printk(KERN_INFO "Unpacking initramfs...\n");
 644                 err = unpack_to_rootfs((char *)initrd_start,
 645                         initrd_end - initrd_start);
 646                 if (err)
 647                         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
 648                 free_initrd();
 649 #endif
 650                 /*
 651                  * Try loading default modules from initramfs.  This gives
 652                  * us a chance to load before device_initcalls.
 653                  */
 654                 load_default_modules();
 655         }
 656         return 0;
 657 }
 658 rootfs_initcall(populate_rootfs);